Vapor and fog generation



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10 Sheets-Sheet 8 E. F. ANDREWS VAPOR AND FOG GENERATION March 22, 1966 Filed April s, 1961 March 22, 1966 E. F. ANDREWS VAPOR AND FOG GENERATION lO Sheets-Sheet 9 Filed April 5, 1961 NN@ @w MI; W

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VAPOR AND FOG GENERATION Filed April 3, 1961 10 Sheets-Sheet 10 532g M1, M, @10,044 v United States Patent O 3,242,098 VAPOR ANI) FGG GENERATION Edward F. Andrews, 105 15th St., Belleair Beach, Fla. Filed Apr. 3, 1961, Ser. No. 100,060 16 Claims. (Cl. 252-359) This application is a continuation-in-part of my copending patent application, Serial No. 595,738, filed July 3, 1956 now Patent No. 3,037,939 issued June 5, 1962. I call attention also to my Patent No. 2,765,578, issued October 9, 1956, which contains generally similar subject matter.

My invention relates to means and a method of vapor generation and for producing a thermal aerosol or fog for purposes of concealment, for controlling atmospheric temperature, for disseminating insecticide or other materials into the outside atmosphere or conned spaces, etc.

Apparatus covered by my invention is well adapted to producing heated vapor under pressure by means requiring little or no mechanical power which is of particular advantage in connection with portable applications.

It is an object of my invention to provide means and a method for vapor and/or aerosol generaiton requiring little or no mechanical power which is simple and economical and otherwise advantageous.

It is a more specific object to generate a fog or aerosol with light, highly portable apparatus which is well adapted to be made in small manually portable form as well as in large units of higher output.

It is a further object to generate a thermal aerosol in such a way as to minimize the exposure of heat-sensitive material to excessive temperature and to reduce the time of exposure thereto.

It is a still further object to provide an improved fogger which is a complete unit except for tanks, connecting lines and electrical connections to supply the pump motor and automatic control and protective systems.

It is a further object to improve the functioning efciency and protection of apparatus of this type.

It is a further object to improve the functioning and equalize the oil distribution of the jet nozzle and establish improved relations of the jet nozzle relative to the fog outlet to produce improved atomization, increased ejector action, effect desired cooling and facilitate the removal and cleaning of nozzle parts and otherwise guard against nozzle obstruction.

It is a further object to improve the flow of combustion air through the device so as to eliminate heat losses, reduce exterior heating and improve its functioning and its eciency.

My invention may take the form of a double-walled duct through which a llow of hot gases is established by means later to be described. Fuel under pressure from its own evaporation or pressurized by other means is supplied to a burner. A vaporizable liquid which may be water, oil, etc., is vaporized in a boiler inside the duct. The vapor under pressure issues from a jet nozzle connected to the boiler and may augment and mix with the flow of hot gases from said duct to form a fog jet with or without insecticide or other material. The insecticide or other material may be introduced through the jet nozzle as subsequently more fully described.

Still further objects and advantages of my invention will be made apparent in the following drawings and description.

In the drawings:

FIG. 1 is a longitudinal cross section of the complete main unit of a fogger adapted for operation on fuels requiring a specially heated vaporizer;

Patented Mar. 22, 1966 ICC FIG. 2 is a cross -section taken on the line 2 2 of FIG. l;

FIG. 3 is a cross section taken on the line 3-3 in FIG. 1;

FIG. 4 is a detail of the male portion of a quick disconnect fitting equipped with a liquid metering orice at one end;

FIG. 4a is a sectional View of the female portion of the quick disconnect fitting adapted for installation on a flexible compression hose and further adapted to engage the male fitting of FIG. 4;

FIG. 5 is a partial cross section of the jet nozzle and air tube assembly showing its position in the outlet cone of FIG. l;

FIG. 6 is a cross section on the line 6 6 of FIG. 5;

FIG. 7 is a diagrammatic view of the fogger unit of FIG. 1 showing the fuel, water and fog material supply and the pump operated from the engine of the vehicle upon which the fogger is mounted;

FIG. 8 shows an embodiment of the invention in which the vaporizer of the main unit of FIG. 1 has oil or other similar liquid supplied to it by a pump and in which the sane pump may supply the same liquid to the burner as fue FIG. 8a shows a modification of the main fogger unit of FIG. 9 or FIG. 1 in which the combustion gases are conducted upward by a right angle housing and separated from the fog jet nozzle. This modication may be specially adapted for operation with the embodiment of FIG. 8;

FIG. 9 shows a longitudinal cross section of the main unit of a fogger especially adapted for operation on LPG fuels;

FIG. 10 is a cross section on the line 1li-1d of FIG. 9;

FIG. l1 is a cross section on the line lll-11 of FIG. 9;

FIG. 12 is a sectional View of the intake end of the fogger of FIG. 9 drawn to a larger scale;

FIG. 13 is a sectional View toward the outlet end of the fogger of FIG. 9, also drawn to a larger scale;

FIG. 14 is a sectional plan view of the burner wheel and scale shown taken on line 14-14 of FIG. 12;

FIG. 15 is a plan View of the control valve and calibrated cylinder of FIG. l2;

FIG. 16 is a cross sectional view of the air tube and jet nozzle mounted in the outlet cone of the fogger of FIG. 9 and drawn to a larger scale taken on line 16--16 of FIG. 17;

FIG. 17 is a view looking into the outlet end of the outlet cone shown in FIG. 16;

FIG. 18 is a cross sectional view taken on the line 18-18 of the jet nozzle of FIG. 17;

FIG. 19 is a diagrammatic view of the main fogger unit of FIG. 9 showing the liquid propane tank, the fog material tank and the water tank. The water pump driven from a vehicle on which the `fogger may be mount-` ed is also shown, together with the connections from the fuel, Water and fog material sources to the fogger.

FIG. 20 shows diagrammatically an embodiment in which the main fogger unit of FIG. 9 is operated Iby utilizing the pres-sure from the l-iquid propane tank to pressurize the water supply to the fogger, the connections between the propane tank, the water tank and the fogger for this operation being shown;

FIG. 21 is a longitudinal cross section of an improved modification of the fogger shown in FIG. 9;

FIG. 22 is a cross section on line 22-22 of FIG. 21;

FIG. 23 is a diagrammatic showing of an improvement of the arrangement shown in FIG. 19 with additional functions and features and with the electrical connections shown for operating the pump motor and other elec- 3 trical features from the battery generator system of the automotive vehicle carrying the fogger;

FIG. 24 is a sectional view of an improved modification of the outlet and nozzle arrangement shown in FIGS. 5 and 17;

FIG. is a view looking into the outlet end of the outlet `cone shown in FIG. 24;

FIG. 26 is a view of the removable nozzle parts and scale trap removed from the nozzle body of FIG. 24, the section taken on line 2626 of FIG. 25.

FIG. 2l illustrates an improved modification of the general type of fogger shown in FIG. 9. inasmuch as there are many similar parts and similar functions in the device of FIG. 2l, a somewhat less detailed description is considered adequate. Although the modification of FIG. 2l is most similar to the modification of FIG. 9, features of other modifications besides that of FIG. 9 may be combined with this modification of FIG. 2l. The legends applied to various of the elements shown in FIG. 21 and arrows indicating direction of fiow of fluids are explanatory thereof taken in connection with this specification. Similar legends and arrows have been applied to other figures in the drawings and for similar purposes.

Referring to FIGS. 1, 2 and 3, these figures show the complete fogger except for the liquid supply system. The complete fogger unit 1t) is provided with an outer casing which may be divided into three parts. The burner housing 12 is removably connected to the body shell 14. The nose 16 is detachably connected to the other end of the -body shell 14. The body shell is supported on rear legs 18 and front leg 20 which may be spotwelded or rivetted to the body shell. The body shell is tubular and may be formed by rolling a sheet of aluminized steel into a tube and spot-welding the seam. The burner housing 12 may be a similarly formed tube having a solid disc 22 seamed into its rear end. An air inlet opening 24 may be provided in the bottom of the burner housing 22. A hinged cover 26 covers an access opening 28 at the top of the burner housing. The burner housing 12 may be attached to the body shell 14 by slipping it over the outside of the latter and fastening it with self-tapping screws. The nose 16 may be attached to the body shell 14 by a ange collar 30 which overhangs an outturned flange at the rear end of the nose. The nose is provided with an opening to permit the passage therethrough of the jet nozzle and cooling tube 32. The nose 16 is formed from a sheet of aluminized steel and is of conical form with an open front end. The joint in the nose cone is not spot-welded but is held together by `screws 34 so that the point can be opened to permit its assembly over the jet nozzle unit 32. A washer 36 is seamed or otherwise fastened into each end of the body shell 14. An inner shell 38 which may be a tube of stainless steel is carried by the washers 36 and projects slightly beyond the Washer at the rear and considerably beyond at the front so as to form an additional support for the nose 16. Thus the interior of the fogger unit 10 forms a duct 40 having an inlet 24 and an outlet 42. Within this duct 40 a coil of steel tubing may be positioned which may constitute the main vaporizer 44. The vaporizer 44 may be carried by three angle strips 46. These may be of stainless steel and spaced around the interior of the inner lining 38. They may be fastened to the inner lining 38 solidly at one end and by means of a screw sliding in a slot at the other end to permit thermal expansion. The rear end of the vaporizer 44 has a straight portion 45 and passes out through the burner housing end plate 22. The front end of the vaporizer coil has a straight portion 47 and is threaded for the attach ment of the jet nozzle unit 32. The jet nozzle unit 32 is secured to the nose by means of the stud bolt and nut 48 which passes through a hole in the top of the nose. The burner vaporizer 50 consists of a coil of steel tubing, one end of which is bent backward and passes out through a hole in the rear disc 22. The other end of the burner vaporizer coil is straight and equipped with a thread which screws into the nozzle support 52. The burner nozzle 54 screws into a tapped hole in the support member 52. The nozzle 54 has a large internal bore reduced to a small nozzle orifice 55 at the end toward the burner vaporizer S0. The size of this nozzle orifice is such as to direct a jet of vaporized fuel at high velocity through the interior of the burner vaporizer 50. The nozzle orifice 55 must be of the proper size to generate the desired heat and to produce an injector action which induces a flow of air into the inlet `opening 24 and also into the opening 28, thence through the duct 40 and out the duct outlet 42. The burner nozzle support 52 may be secured to the end plate 22 by means of a bolt and nut 56 attached to the nozzle support 52. The rearwardly bent straight portion of the burner vaporizer coil 50 may be secured to the burner housing 12 by means of a U-clamp 58 which may be attached to the burner housing by self-tapping screws. This U-clamp 58 together with the bolt and nut 56, securely supports the burner vaporizer 50. The burner vaporizer is surrounded by a vaporizer shell 6i) which extends from the forward end of the vaporizer coil rearwardly to a point roughly mid-way between the burner nozzle and the rearward burner vaporizer coil. The vaporizer shell 6l) carries a vaporizer generating pan 62. This is preferably provided with a pad of glass cloth covering its bottom. This can be saturated with an appropriate fuel and ignited to generate the burner when the device is first started i.e., to generate the fuel as a gas. If the burner fuel is used for generation, this may be supplied through the starting tube 64 which connects through the starting valve 66 with the burner control valve 68. The starting valve supplies fuel to the pan without filling the vaporizer coil 50. The burner control valve may be screwed yonto a thread on the rearwardly extending end of the burner vaporizer 50. The valve 68 should meter the fuel accurately at specific angular settings. A heat insulation space 70 is provided between the lining 38 and the body shell 14. This may be filled with a heat insulation material such aS Vermiculite. It also may be left empty. The diameter of the turns of the main vaporizer 44 may be larger at the rear of the vaporizer to provide additional -space for the burner llame without direct contact with the vapor- `izer coils. The angle strips 46 may be cut down in height toward the rear end to accommodate these larger vaporizer turns. The fog oil supply tube 72 is -connected to the lower end of the vaporizer jet nozzle 32. This is attached to the burner housing at the rear end by a support 74. Three connecting means are provided for t-he liquid supply to the fogger unit 10. These may be of the quick detachable type. The male member `of a fitting of this type is shown in FIG. 4. One of these male members 76 may be connected to the fog oil supply tube 72. It will be noted that the male fitting 76 is provided with a plug pierced by a small orifice 78. The size of this orifice is such as to supply the desired amount of fog oil or formulation to the vaporizer jet nozzle 32. Different sizes of orifice 78 may be employed to meet different conditions or an adjustable orifice or valve may be used if desired. A similar male fitting 76 is also screwed on to the straight rear portion 45 of the main vaporizer 44 where it projects through the rear disc 22. In this case, the orice 78 may be varied in a similar manner to control the liquid supply to the main Vaporizer 44. The function of these orifices 78 will be more fully described. A male fitting 77, but without the plug and orifice 78, is attached to the fuel control valve 68, which valve performs the function of the orifice 78 in regard to the fuel supplied to the burner. Flexible liquid lines may be connected to the fittings 76 and 77 by means of a quick detachable female fitting 80 shown in FIG. 4(a). By means of the fitting 80, the liquid c' J lines may lbe quickly attached and detached to the fogger unit 10. The hinged cover 26 provides ready access for cleaning the burner nozzle 54 and may be opened yfor lighting the generator or for inspecting the fire. Additional air is also supplied under the right and left end of the cover 26. Reference is now made to FIGS. and 6 which show the details of the vaporizer jet nozzle unit 32. The nozzle body 82 may be made of stainless steel and has an external thread on the rear and adapted to screw into the forward end 47 of the vaporizer coil 44. The other end carries an internal thread into which is screwed the expanding nozzle mem- ;ber 84. The nozzle orifice 86 is closely concentric with the tapered bore of the nozzle member 84 and is connected to the interior of the vaporizer 44 yby an enlarged bore 88. At the bottom of the nozzle body 82 between the nozzle orice 86 and the threaded portion of the nozzle member 84 is an opening 90. Into this opening, a stainless steel tube 92 may lbe silver-soldered or welded. To the other end of this tube 92, an elbow 94 may be silver-soldered with a suitable screw connection for attachment of the tube 72. The front end of the nozzle member 84 carries serrations 96. The lower front surface of the body 82 is also provided with a slot 98. A wire spring 100 is urged into this slot 98 and the serrations 96 to lock the nozzle member 84 against angular movement. The liquid supply tube 92 communicates with an annular space 102 which surrounds the rear end of the nozzle member 84. The member 84 is screwed in to a point which leaves an annular aperture 104 of the proper width. Through this annular aperture which surrounds the vapor jet issuing yfrom the nozzle aperture 86 the fog producing or treatment material is sucked Iin to the vapor jet by the venturi action of the jet. The annular aperture 104 should be of such width as to provide adequate vacuum and to avoid plugging. It will be seen that this construction provides an uninterrupted annular passage 104 so that an uninterrupted ring of t-he liquid to be atomized is expose-d to the periphery of the jet. This tends to increase the quantity that can be iinely atomized. The expanding bore of the member 84 extends for a short distance forwardly from the annular orice 104. If the bore of the member 84 is made the proper amount larger than the bore 86 a fairly high vacuum can be obtained. This facilitates atomization and raising of the liquid to be atomized a considerable distance if desired, especially when adequate pressure is maintained in the vaporizer 44. The annular `grooves 106 are for the purpose of thermally isolating the liquid in the space 102 from the hot rear portion of the nozzle body. It is desirable to keep the liquid to be vaporized reasonably cool to prevent -carbonization of insecticide which might plug the nozzle and also to prevent the overheating of any insecticide or treatment material contained in the liquid to be vaporized. This purpose is also served by the jet nozzle cooling tube 108 which surrounds the forward portion of the body 82 and also the tube 92. The vapor jet issuing from the nozzle member 84 passes through an aperture 110 in the tube 108. This jet induces a ilow of cool outside air into the bottom opening 112 which passes over the tube 92 and the body 82, ycooling them and shielding them from the hot combustion of gases issuing from the duct outlet 42. Further, this cool air passing out the orifice 110 surrounds the jet of vapor and treatment material as it passes out the outlet 42, thus tending to shield the fog jet from the hot gas ow which surrounds it. This arrangement has been found to be advantageous when certain fogging materials are -used and it permits higher gas temperatures and tends to prevent carbonization of nozzle parts. A plug 114 may be pressed into the top of the cooling tube 108. This plug 4may carry a bolt and nut combination 48 which connects the jet nozzle unit 32 to the nose 16. A nut 116 clamps the tube 108 to the nozzle body 82. The tube 108 is `slotted on its forward side as indicated at 118 so that the assembly of the nozzle body 82, tube 92 and elbow 94 can be passed to the interior o-f the tube. A curved plate 120 is then attached to the front of the tube 108 to cover he slot. The plate 120 is held by the screw 122 and the inturned lip 124. The screw 126 -holds one end of the spring 100 to the plate 120 which plate has a hole registering with the hole 110.

Referring now to FIG. 7, the fogger unit 10 previously described may be mounted on an automotive vehicle such, for instance, as a jeep or truck indicated by the number 128. Two L-shaped brackets 130 and 132 may be attached to the vehicle and the feet of the fogger unit 18 and 20 may be bolted to the horizontal member of these brackets. Due to the relative lightness of the fogger unit 10, this mounting means is adaquately strong. The outlet end or front of the unit 10 may be directed rearwardly and outwardly with relation to the vehicle so that the jet is projected in such a way as not to eddy behind the vehicle when moving. The direction of the jet can of course be altered by varying the position of the unit 10 relative to the vehicle. For the embodiment of the invention now being described, three separate liquid sources may be employed. Two of these liquids may be supplied under pressure, one to the burner connection 76 and one to the vaporizer connection 45. As shown in FIG. 7, water or other liquid may -be supplied under pressure from the pump 134 which may be a gear pump or other suitable pump driven by means of a belt 136 from the engine power take off 138 associated with the vehicle 128 and supplied with power from its power source. The water is supplied from the tank 139 to the intake of the pump 134 through the pipe 140 and shut off valve 142. The water under pressure is delivered to the vaporizer connection 45 through the pipe 144 and flexible connection 146. The pressure of the water supply may be indicated by a gauge 148. The water pressure may be held near to the desired pressure with a spring-loaded liquid by-pass valve which may be integral with the pump 134. This by-pass valve 150 has a ball valve 152 held against its seat by a compression spring, the force of which is Varied by the adjustment screw 154. The spring side of this valve is connected to the pump intake and the opposite side of the valve to the pump outlet. Thus, when the outlet pressure exceeds the spring-loading of the valve, water is by-passed back to the inlet. By incorporating the by-pass valve 150 with the pump 134 and having passages of short length and large area, closer pressure regulation may be obtained. The water supply under pressure in the pipe 144 is also communicated to the fuel tank 156 through the pipe 158 and valve 160. A baffle 161 is provided Where the water enters the tank 156 to prevent it from squirting upward. The fuel which may be for instance No. 1 furnace oil or kerosene is shown at 162 occupying the upper portion of the tank 156. The tank is equipped with a sight level gauge 166. Pressure is applied to the fuel 162 in the tank 156 by water 164 pumped into the bottom of the tank by the pump 134 through the pipe 158. As the fuel 162 is lighter than the water 164, it oats on the water and may be displaced into the exible connection 168 which connects to the fitting 77 carried by the fuel valve 68. However, it may be desirable to supply fuel to the burner at a somewhat lower pressure than that generated by the pump in the water line 158. Thus a pressure regulating valve 170 may Abe employed to regulate and reduce the pressure in the line 168 below that in the line 158 and the tank 156. A gauge 172 may be employed on the outlet side of the reducing valve 170 showing this lower pressure. The regulating valve could also be installed in the line 158 and the line 168 connected directly to the tank if desired. The drain valve 174 may be opened to drain the water out of the tank 156 after it has been filled with water and all of the fuel displaced. After the tank is drained, it can then be refilled with oil through the pressure seal filler cap 176. The level of the fuel can be seen at all times in the sight gauge 166. After the water is drained, the valve 174 is closed before the tank is refilled with fuel. The tank 178 contains the supply of fog oil, insecticide or any formulation material 180 which may be employed. The tank 178 may be filled through an appropriate filler cap. A stand pipe 182 extends to the bottom of the tank and is connected to a valve 184 for shut off and/or adjustment of flow. This valve is connected to a strainer 186 which supplies the material 180 through the flexible connection 188 to the connection 76 and the pipe 72 which in turn connects to the pipe 92 attached to the jet nozzle body 82. It will be understood that tank 178 rnust be so positioned that the suction generated in the jet nozzle orifice 102 is sucient to raise the desired amount of the material 180. The tank may be above or below the level of the jet nozzle but must not be too far below and is generally located at or somewhere near the same level. One advantage of the lower tank is that no fog material can siphon out when operation is discontinued. The water tank 139 must also be positioned so that the pump 134 can raise the water and it may be preferable to position the water tank 139 with its bottom somewhat above the pump intake, especially when a low lift pump is employed. All three of the tanks 139, 156 and 178 may be mounted on the vehicle 128 which carries the fogger 10. If little or no portability is required the fogger may be mounted on a stand adapted to rest on the ground and the water under pressure may be supplied if desired from a municipal water faucet instead of from the tank 139 and the pump 134. If the municipal water pressure is too high or not sufficiently constant, a pressure regulator similar to the pressure regulator 170 may be connected between the municipal water faucet and the pipe 144 which may be broken at any convenient point to substitute the municipal water supply for the pump 134. FIG. 8 shows an embodiment of the invention quite similar to that of FIG. 7 except that a liquid such as No. l or No. 2 furnace oil is supplied to and vaporized in the vaporizer 44. This material may also be used for burner fuel, thus eliminating the necessity of a separate fuel tank. The common fuel and fog oil tank is given the number 139. The fuel and fog oil from the tank 139' is supplied through the pipe 140' to the pump 134 and through the flexible connection 146 to the rear end of the vaporizer 45. The fuel is supplied from the pump 134 through the reducing valve 170', the flexible line 168 to the burner fuel supply fitting 177. The formulation material is supplied to the jet nozzle supply pipe 72 from the tank 178 through the valve 184', strainer 186' and flexible connection 188' in the same manner as described in the embodiment of FIG. 7. It may be mentioned that the orifice in the detachable connection 76 of FIG. 4 in the vaporizer connection 45 and the formulation connection 76 Will most likely be of a different size than those employed in the embodiment of FIG. 7. A larger volume of fog can be produced when a fog forming material such as oil is used in the vaporizer instead of water. Also the weight of the water and tank is avoided.

Referring to FIGS. 9, l0, ll, 12 and 13, these figures show a further embodiment of the invention especially adapted for operation on fuels of the character of propane, butane, etc., known commercially as liquid petroleum gas or LPG FIG. 9 shows the fogger unit 300 for operation preferably, but not necessarily, on` liquid propane. This unit is supplied with water, gas and fog oil as shown in other figures and later more fully described.

As shown in FIGS. 9, 10, ll, 12 and 13, the outer casing consists of an elongated cylinder carrying an outlet cone at one end and a burner plate at the other. The burner may be supported on the burner plate 302 which is connected to the body shell 304 by spacing members 306. The annular space between the burner plate 302 and the body shell 304 constitutes the air intake through which the flow of air is induced by the injector effect of the burner. The outlet cone or nose 308 is detachably clamped to the flanged outlet end of the body shell 304 by means of a bead at the large end of the nose 308 which is drawn up in clamping relation to the outturned flange by the screw clamp 310. The body shell is supported on rear legs 312 and front leg 314. The body shell 304 may be formed `of a single sheet of aluminized or other suitable steel rolled into a tube with the ends welded or otherwise secured together. The nose 308 may be formed into conical shape from a flat sheet and the overlapping ends detachably secured together with screws to permit it to be assembled around the jet nozzle and air tube assembly 342 later t0 be described. An inner shell 316 may be a tube of stainless steel rolled up with the Iabutting or overlapping ends secured together, for instance by welding. Within the duct formed by the inner shell 316, a coil of steel tubing is positioned forming the vaporizer 318. Combustion gases from the burner pass mainly through the interior of the vaporizer coil. Thus, the vaporizer 318 shields the inner shell 316 and the inner shell shields the outer shell 304 from the heat of the burner. This reduces heat losses as well as reducing the temperature of the outer shell. The vaporizer is supported by angle fins 320 which may for instance be four in number. These fins are secured to the inner shell 316 near the outlet end by bolts 322 passing through the bent over portion of the fins 320 and through the inner shell 316 and clamped by a nut. The bottom one of these bolts 322 screws into a spacer nut 324 which together with the other bolts 322 space the inner shell 316 from the outer shell 304 near the outlet end. The spacer 324 is in turn fastened to the outer shell 304 by the bolt 326. This is the only point of fixed attachment between the outer shell 304 and the inner shell 316. Near the intake end, the inner shell 316 is spaced from the outer shell 304 by the bent over ends 328 of the fins 320. These ends are positioned by slots 330 in the intake end of the inner shell. The ends 328 are in turn prevented from inward displacement by the pieces 332 which are wider than the slots and are welded to the ends 328. The ends 328 are free to move axially in the slots 330 and also with relation to the outer shell 304 so that the parts can accommodate themselves to the expansion and contraction resulting from heating and cooling. The single attachment between the inner and outer shell by the bolt 326 also permits free expansion and contraction of the members, especially in their direction of greatest length. Supporting the inner shell on the four ends 328 also makes for easy fitting on assembly. The intake end 334 of the vaporizer 318 passes out through a hole in the burner plate 302. The outlet end of the vaporizer has a straight portion 336 which is threaded for attachment of the steam strainer 338 which encloses the strainer screen 340. The jet nozzle unit 342 which will be later more fully described is attached in turn to the outlet end of the steam strainer 338. The jet nozzle unit 342 passes through suitable holes in the top and the bottom of the nose 308 and is attached thereto by means of the drip trough 344 which is in turn fastened to the unit 342 and to the nose 308, for instance by means of screws. The drip trough prevents liquid drip from running into the body where it might cause combustion. The burner tube 346 is secured to the end plate 348 which carries a mixing tube 350 which passes through the plate 348 and is threaded at the end. The mixing nozzle 352 screws on to the threaded end of the mixing tube 350 and clamps the burner unit as a whole to the burner plate 302. The other end of the mixing nozzle 352 is threaded for attachment of the burner valve 354. The burner valve unit 354 is provided with a strainer housing 356 containing a fuel strainer, not shown. It is also provided with a boss into which the pilot light valve 358 is screwed. The pilot light 360 is supplied with gas from the gas valve unit 354 by means of the connecting tube 362. Air is supplied to the pilot light through the orifice 364 which, together with the small bore gas oritice (not shown), constitutes a Bunsentype burner. This is directed upwardly toward the burner tube 346 and made less subject to blow out by means of the U-shaped strip 366 which covers the end of pilot light 3160 in closely spaced relation. In one leg of the U member 366, a hole is provided which its tightly over the pilot light 36@ and the two parts mayr also be welded together or otherwise fastened. The pilot light 360 is secured to the burner plate 362 by means of a bracket 368. The gas inlet end of the burner valve 354 is provided with a male element of a quick disconnect fitting similar to that shown in FIG. 4. Fuel is supplied to this through the female portion of a quick disconnect tting similar to that shown in FIG. 4a which in turn may be connected to a suitable pressure hose which in turn connects to the source of propane or other fuel as will be later more fully described. The burner valve 354 includes a needle-type of valve, not shown, which is raised more or less off its seat by rotation of the burner valve wheel 370. The wheel is connected by the valve shaft to the burner scale 3'72 shown in plan View in FIG. 14. The figures on the scale 372 are read against the burner indicator 374 and by setting the scale so that the proper number comes opposite the indicator, a predetermined burner setting to supply the desired amount of heat may be made. After the fuel passes through the burner valve, it is discharged in a jet through the nozzle orifice 376. Primary air is induced by this jet through the air inlets 378, and mixing occurs in the mixing tube 350. Burning and mixing with secondary air occurs in and adjacent the outer end of the burner tube 346, which also acts as a ilame holder. The straight inlet end 334 of the vaporizer 318 passes out through a hole in the burner plate 302. This inlet end is threaded Ifor a T fitting 330. In the upper opening of this T is mounted a steam pressure gauge 382 which indicates the steam pressure in the vaporizer 318. Into the third opening of the T 380 may be screwed the male member of a quick detachable titting 384. This fitting is provided at its inlet end with a small orifice 386. This oriiice is similar to the oriice 78 shown to a larger scale in FlG. 4. The titting 384 is also similar except that it has a male thread on the end which screws into the T 389. The end of the pressure hose 388 through which water is supplied to the vaporizer is attached to a quick connector fitting shown to a larger scale in FIG. 4a. This iitting S can be quickly connected to or disconnected from the litting 384. The oriiice 386 is also proportioned so as to permit the passage of the proper amount of water to maintain the desired pressure in the vaporizer as indicated by the gauge 382. This pressure may be for instance forty or titty p.s.i., but of course a different pressure may be employed if desired. The supply of water under pressure to the hose 388 will be later more fully described. Fog oil or any desired formulation, with or without insecticide, is supplied through the hose 390 which connects to a similar quick connector fitting 392. This is detachably connected to the fitting 394 to supply the formulation to the formi lation control valve 396. This valve has a manually Operable cylindrical scale 398 which is read against the ar-row 400. The valve 396 may be a needle valve and when the cylinder 398 is turned to the right, it is fully closed and reads zero. When it is turned to the left, the needle Valve is screwed up ott the seat and permits the iiow of formulation .depending on the degree to which the Valve is opened. The desired flow of formulation is secured by opening the valve to a number corresponding to the desired rate of ow. A dryer fog is produced by a smaller opening of the valve and a wetter fog when the valve is more widely opened. With maximum rate of ow large bore lines and tittings should be provided. The valve 396 is connected to a T member 402 which also receives the threaded end of the fog oil or -formulation line 404. Into the third opening of the T 402 is screwed a vacuum gauge 406 which indicates the vacuum created by the liow of steam from the jet nozzle later to be described. This vacuum causes the fog oil to tiow through the valve 396 and the pipe 484 to the jet nozzle. It is desirable to seal the annular passage between the outer or body shell 304 and the inner shell 316. This is done by means of the washers 498 between which is interposed a refractory sealing material 41@ which may be, for instance, asbestos wicking. The washer 408 toward the inlet end is held in axial position by the bolts 322 and the washer toward the outlet end is held by the screws 412. This arrangement and also the way in which the outlet cone 388 is clamped to the body shell 304 is best shown in FIG. 13.

Referring now to FIG. 16, the outlet cone 308 carries the air tube and jet nozzle assembly generally designated as 342. The assembly 342 is secured to the tail cone 308 by means `of the fitting which supports the drip trough 344 which in turn is secured to the air tube assembly by the screws 416.

Referring now to FlGS. 16, 17 and 18, the fog oil line 484 connects by means for instance of a compression fitting, not shown, to the fog oil tube 418. This tube is connected by a special fitting 42@ to the riser tube 422. The iitting 424i is iirrnly held by a slot in the bottom of the air tube 424, the edges of which engage slots in the fitting 420. The upper end of the riser tube 422 is inserted into a hole in the jet nozzle body 426. This tube 422 may be silver soldered into the nozzle body and also into the fitting 420. The steam iitting 428 is screwed into the small threaded bore in the nozzle body 426 and clamps the nozzle body to the wall of the air tube 424. The intake end of the steam iitting 428 screws into the strainer housing 338. The multiple nozzle member 430 tits into the nozzle body 426 and forms a tight seal between the steam passage 432 and the fog oil passage 434. The annular passage 434 communicates with the interior of the tube 422. The nozzle outlet member 436 carries an external thread which engages a thread at the outlet end of the nozzle body 426 locking the multiple nozzle unit 430 in place. Between the members 430 and 436 is a flat conical space 438 which extends outwardly beyond the multiple steam nozzles 440 an-d the multiple fog oil nozzles 442. The space 438 connects to the annular fog oil passage 434 by means of a straight slot 444 in the multiple nozzle member 430. Thus a steam jet issuing from the multiple steam nozzles 440 and passing through the larger diameter fog oil nozzle holes 442 is completely surrounded by fog oil which lls the thin conical space 438. The diameters of the holes 448 are :about .086 inch and the diameters of the holes 442 are about .120 inch. Thus the holes 440 are near 70% of the diameters of the holes 442. This relation has been found to give good operation. The high Velocity steam jet issuing from the nozzles 440 expands, and entrains and projects outwardly any fluid in the space 438, thus creating a vacuum and sucking up the fog oil from the tube 418 through the tube 422 through the annular passage 434 through the slot 444 into the space 438 and out the multiple fog oil nozzles 442. The steam nozzle 444i and the fog oil nozzles 442 diverge outwardly from the central axis at an angle of about 15. If this angle is too large low axial velocity and fog oil ignition may result. lf the angle is too small mixing with the hot gases is reduced and the fog may be wetter. Attention is called to the fact that the multiple fog oil nozzles 442 must be located coaxially with the multiple steam nozzles 44). This relation is insured by inserting one or more rods, the small diameter of which fits the holes 440 and the large diameter of which tits the holes 442. The member 436 is screwed up tight with these rods in place. ln fact, the torsion may be applied by means of these rods. After the retaining member 436 is tightened up, the rods may be removed and the two sets of multiple bores Will then be in proper alignment. Attention is called to the ejector effect of the steam jets issuing from the fog oil nozzles 442. This ejects air from the inside of the air tube 424 which causes a flow of air into the top and the bottom of the air tube and out through the air tube nozzle orifice 446. This fiow of air prevents the hot combustion gases issuing from the outlet cone 308 from overheating the fog oil in the tube 422 and the nozzle boy 426. It is especially desirable to avoid overheating of the fog oil when it carries a formulation of, for instance, insecticidal material which may be decomposed and rendered relatively ineffective by excessive heat. The cool air ejected out of the orifice 446 also reduces the effect of the hot combustion gases on the atomized or vaporized formulation issuing from the nozzles 442, the jets from these nozzles are surrounded by the hot gases issuing from the outlet cone 30S, and the outward ow of the combustion gases are augmented by a second ejector effect of jets. By employing a multiple nozzle having a total area such as to produce the proper liow of steam, a longer contact line is obtained between the periphery of the steam jets and the fog oil in the space 438. This is beneficial to line atomization. The multiple nozzle is also beneficial from the point of view of better augmentation of .the flow of hot gases and reduction of aerosol particle s1zes as the result of better mixing with the hot gases.

Referring now to FIG. 19J the supply of formulation or fog material to the fog oil hose 388 will now be described. The fog oil may be contained in a fog material tank 448 having a vented filler cap 450. This tank is preferably not too high from bottom to top so as to reduce the difference in gravity head from when the tank is full to when the tank is nearly empty. The tank may be provided with a pipe 452 running to near the bottom where it may carry a strainer 454. A shut off valve 456 may be provided by means of which the tiow of fog material may be cut off to stop fog generation without altering the setting of the valve control valve 396. The valve 456 may be connected to the control valve 396 by means of the hose 390 and the quick disconnect fittings 392 and 394. The control valve 396 in turn connects to the fog oil pipe 404 through the T fitting 402 carrying the gauge 406 which shows the reduction of pressure in the fog oil line.

The fuel, which may be for instance liquid propane, may be contained in a pressure tank 458. This is provided with `a `shut off valve 460. This valve is connected by a pipe 462 to a pressure reducing and regulating valve 464 which, by means of a properly arranged springbalanced diaphragm, maintains a desired pressure on the outlet side to which may be connected a fuel pressure gauge 466. This may be connected by a flexible pressure tube 468 and quick disconnect fittings 470 and 472 to the burner valve 354 from which the gas may be supplied to the nozzle orifice 376 as previously described. If liquid propane is used for fuel and if the tank 458 is sufiiciently large rela-tive to the amount of fuel being used, sufiicient vaporization will occur within the tank except at quite low atmospheric temperature. If fuels of higher boiling point are employed or use at lower temperatures intended, some form of vaporizer may be employed such, for instance, as that shown in FIG. l or some other type. Also by application of extra heat to the fuel tank operation may be made satisfactory at lower temperature.

Water or other liquid may be supplied to the inlet end 334 of the vaporizer 311.8 from a water tank 474. This water tank may be considerably smaller if desired than the fog material tank 448 as much less water may be used than fog oil during a given period of fogging. The water tank is provided with a vented filler cap 476. In this embodiment, the water tank may be made of light material as it is not subject to pressure. The water tank 474 is connected to a water pump 478 through a pipe 488 which may be equipped with a shut oft" valve 482. The pump 478 may be for instance a `small gear pump and may be driven from the engine 485 in the vehicle carrying the fogger by means of a belt 484. Other types of pump may also be employed. The pump 478 may be equipped with a spring-loaded by-pass valve 486 which is interposed between the inlet and outlet and is adjusted to by-pass water from the outlet to the inlet through this spring-loaded valve when the pressure exceeds a given value occasioned for instance by the speeding up of the pump drive by acceleration of the vehicle motor. The outlet of the pump 478 may be connected to a water pressure regulator 488 by a pipe 49@ if closer pressure regulation is desired. The outlet side of the pressure regulator 488 carries ya gauge 492 and a flexible pressure hose 388. The water supply under the pressure determined by the setting of the pressure regulator 488 is thus maintained on the water supply side of the water orifice 386 in the fitting 384. Thus the water gauge 492 shows the water pressure on the inlet side of the orifice 386 while the steam gauge 382 shows the water or steam pressure on the vaporizer side of the orifice 386. The -size of this orifice and the pressure difference on opposite sides thereof determine the ow of water into the vaporizer.

By varying the size of the orifice 386 and by varying the water pressure, the fogging rate, the character and micron size of the fog can be influenced. Also, the amount of water or other liquid consumed with relation to the amount of formulation put out in the same period of time.

Referring now to FIG. 2f), there is shown an embodiment in which the fogger unit 300 and fog material tank 448 may be the same and in which the same parts are designated by the same numbers as in FIG. 19, but other parts are given higher numbers. However, water or other liquid under pressure is supplied to the end 334 of the vaporizer 3];8 by the pressure of the vaporized propane supplied from the propane tank to the burner. The propane tank 494 is provided with a shut off valve 496, similar to that described in FG. 19. A pressure regulator 498 is connected to the valve 496 by pipe 500. The pressure regulator 498 may be connected to a T fitting 502 by a connection 504 which is equipped with a pressure gauge 506. One opening of the T fitting 502 is connected to the tiexible pressure hose 468 to supply fuel to the burner valve 354. The water tank 508 is constructed to withstand considerable pressure. It is provided with a pressure release or safety valve 510 which is set to release the pressure at a value considerably below that which the tank 50S can safely hold. The tank 503 may be filled with water or other liquid to be supplied to the vaporizer by means of a tightly sealing filler cap 512. A connection 514 from the tank 508 carries a shut-off valve 516. This is in turn connected to the T fitting 502 by a connecting pipe 518. Thus the pressure of the vaporized propane, or other low boiling point fuel, in the tank 494 may pass through the open valve 496, the connection 560 to the pressure regulator 498 where its pressure is reduced to for instance 50 p.s.i. The gas then passes through the connection 584 to the T fitting 502, the pressure being indicated by the gauge 586. This pressurized gas then passes through connection 518, valve 516 and connection 514 to the tank 508 where the pressure of the gas is supplied to the water or other suitable liquid in the tank 508. At the bottom of the tank 508 a shut-oli? valve is provided communicating with the water in the tank. When this valve is open, water is supplied through the pressure hose 388, one end of which may be connected to the valve 520. The water in the hose 388 is supplied under the pressure indicated by the gauge 506 to the water inlet side of the orifice 386 through which it is fed to the inlet end 334 of the vaporizer 318. It will be seen that with this arrangement the same pressure will be supplied to the burner valve 354 that is supplied to the water tank 508 and to the inlet side of the water orifice 386. Both the water pressure to the vaporizer and the gas pressure to the burner may be controlled simultaneously by the pressure regulator 498. It will be seen that this constitutes a simple and effective Way of supplying liquid under pressure to the vaporizer without the use of a pump. However, a heavier water tank S08 is required when the tank itself is subject to the pressure instead of the pressure appearing only at the outlet side of a pump as shown in FIG. 19. When liquid propane is employed in tank 494 and water in tank 508, there is a certain amount of absorption of the gas by the water if they are allowed to stand for extended periods of time in contact with each other under pressures substantially above atmosphere. When suicient gas is absorbed by the water, there may be a tendency for the pressure in the vaporizer 318 to show fairly large and more or less periodic fluctuations. For this reason, it is desirable to release the gas pressure on the water tank and/or drain the water from the tank during extended periods of non-use. No additional loss of gas will result if the water tank 508 is completely lled with water through the ller 512 before operation is resumed. The gas used for pressurizing the water is only equal to the volume of water displaced at the water supply pressure and appears to be substantially less than 10% of the gas used by the burner in certain applications. This method of pressurizing the water supply makes the operation of the fogger independent `of any power source such, for instance, as the engine 485. The tank 508 may be provided with a water gauge 524 by which the remaining supply of water can be determined at any time. The valve 520 may also be provided with a water drain cock 526 by which water saturated with gas may be drained off. It will be understood that gas other than propane may be employed and liquid other than water may be supplied to the vaporizer 318 by pressurizing the liquid supply with pressurized gas. However, the gas and the liquid selected must be such that the gas will not be too readily soluble in the liquid. This pumpless system may be of special advantage for certain applications, for instance in a small manually portable unit, or where power to drive a pump presents difficulties.

The operationof the embodiment shown in FIGS. 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19 will rst be described. As there is much similarity in the operation of all embodiments, it will not be necessary to describe each in complete detail. After the operation of the embodiment covered by the above-mentioned gures has been explained, the differences of operation of the other embodiments from this one will be brought out.

The fogger unit 300 may -be mounted on some automotive vehicle, for instance a Jeepf The fog material tank 448, the propane or LPG tank 458 and the water tank 474 may be mounted in the body of the Jeep The Iwater pump 478 may be driven from the Jeep engine 485. Other means of vdriving the pump 478 which requires only relatively small power may alternatively be provided. It is preferable to mount the fog material tank 448 so that its top is slightly below the horizontal center line of the fogger unit 300 so that fog material or fog oil will not siphon out when the fogger is not oper- 14- ating. The water tank 474 may be mounted slightly above the pump 478 so as to avoid raising the water to the pump intake. To start the fogger in operation, the Valve 460 on the propane tank 458 is first opened. The pressure `regulator 464 is then adjusted to supply the desired pressure to the burner. The pilot light valve 358 is then opened and the pilot light 360 lit by applying a flame to the lighting hole 361. At this point the Jeep engine 485 should be in `operation and driving the pump 478. The water valve 482 should be open. Water will then flow from the pressure hose 388 through the orilice 386 into the straight intake end of the vaporizer 334 through the vaporizer 318 through the straight outlet end of the vaporizer 336 into the steam strainer 338 into the nozzle body 426 and through the multiple steam passages 44@ and out the openings 442. After Ithe presence 0f wate-r in the vaporizer 318 is assured, the burner valve wheel 378 is turned so that the burner scale 372 is open for instance to 8. Gas will then tiow through the partially opened burner valve and issue as a jet from the mixing nozzle 376. The jet induces a ow of air into the mixing jet air openings 378 and through the mixing tube 359. This mixture of air `and gas then issues from the open end of the burner shell 346 and is ignited `by the llame of the pilot light 359. The gas pressure regulator Valve 464 may then be adjusted so that the fuel gauge 466 reads for instance 30 p.s.i. The water pressure regulator 488 may then be adjusted so that the water gauge 492 is for instance 50 p.s.i. A mixture of water and steam will then issue from the openings 442. This will very shortly become dry superheated steam, if the burner valve adjustment has been properly made. The pressure in the vaporizer 318 will then approach a steady pressure for instance 40 p.s.i. as shown by the steam gauge 382. lf the 'setting of the burner valve is too low, the steam issuing from the openings 442 will be wet and clearly visible to the eye. The burner setting can then be slightly increased until the steam is dry and invisible. If the burner valve setting is too high, the steam gauge 382 will be unsteady and may show fairly large uctuations. This `can be corrected -by reducing the gas supply to the burner by setting the burner dial to a lower number. When the proper setting of the burner dial is attained, the steam pressure in the vaporizer as indicated by the gauge 382 will be relatively constant. During the starting period, the fog material shut-oit valve 456 and/ or the fog material control valve 396 should be closed so that no fog material is delivered to the conical fog oil space 438. Under these circumstances, the vacuum created by the jets from the multiple steam nozzles 440 passing out through the fog oil openings 442 will be transmitted from the space 438 through the slot 444 through the annular passage 434 through the tube 422 through the tting 420 and the tubes 418 and 404 to the T member 4112 and will be indicated by the vacuum gauge 406. This might show for instance a vacuum of 20 inches. However, after the steam pressure in the vaporizer has been stabilized, the fog oil scale 398 may be opened for instance to eight which may give a moderate fogging rate. The shut-off valve 456 may then be opened and fog oil or fog formulation will be raised from the tank 448 through the strainer 454 through the tube 452 and valve 456 to ilexible tube 398, quick disconnect fittings 392 and 394 through control valve 39d into T member 402 and thence to the fog oil space 438 by the path described for the communication between this space and the vacuum gauge. The fog oil in the space 438 surrounds each of the steam jets issuing from the multiple jet nozzles 440 and a mixture of superheated steam and fog -oil vaporized and atomized to form an aerosol issues from the multiple fog oil openings 442. Cool air from the interior of the air -tube 424 is also picked up by the multiple jets and passes out the opening 446 therewith. These jets in turn mix with and augment the llow `of the hot gases issuing from the outlet cone 308. This flow of steam,

fog oil and hot gases forms a high velocity jet which is projected axially for a considerable distance behind the outlet end of the nose 308. if it is desired to have the fog very dry, the scale 398 of the control valve 396 may be set to a lower number. The rate at which formulation is delivered in the form of fog will then be somewhat lower. On the other hand, if it is desired to increase the rate of formulation delivery, the scale 398 is set to a higher number and may even be opened to a second or third turn depending on the construction of the valve. When the control valve 396 is opened, a large amount of formulation may be delivered per unit of time, such for instance as gallons per hour. For highest delivery the bore of the whole fog oil line must be large and free of restriction. Also the fog oil lift should be minimized. Under `these conditions, a wetter fog containing more large sized droplets will be delivered. A finer particle size and a dryer fog can be provided without reducing the rate of formulation delivery by setting the burner valve to a higher number to supply more heat to the vaporizer and to the hot gases issuing from the nose 3138. A larger and hotter supply of steam may also be provided. However, if the burner is set too high, without increase in the water supply, fluctuations in the steam pressure may be encountered. Also, an excessively high setting of the burner valve together with a high setting of the formulation control valve 396 might cause ignition of the fog if the formulation is highly inflammable. If a fog oil such as No. 2 furnace oil is employed, more than thirty gallons per hour may be fogged with no tendency whatever to ignition of the fog oil. In fact, if the fog close to the nose 308 is ignited from the outside with a torch, it will immediately put itself out. If it is desired to briefly discontinue fogging, the shut-off valve 456 may be closed, thus interrupting the delivery of fog material. During this time, the burner will still continue to operate and steam will still issue from the multiple jet nozzles. Fogging can then be resumed at any time by merely again opening the valve 456. It is desirable to place this valve within reach of an operator on the Jeep so that the fog can be turned on and off quickly. Remote control of the valve 456 by means for instance of a flexible shaft may alternatively be provided. If it is desired to discontinue operation for a longer time7 the burner valve 354 and the water valve 482 may both be closed. The pilot light 360 may continue to `burn during the shut-down so that restarting is effected by simply opening the burner valve 354 and the water shut-off valve 382, the burner being again relit from the pilot light. Due to the fact that the fog material supply in the tank 448 and the water supply in the tank 474 are not subjected to pressure, the filler caps 450 and 476 respectively can at any time be removed to determine the amount of liquid still remaining in the tanks. The supply of liquid propane in the tank 458 may be determined for instance by keeping a record of the time that the burner operates. Tanks of propane gas suitable for this purpose are available commercially and when empty may be exchanged for full tanks. Suitable equipment is also available for refilling the same tank from a private supply of liquid propane. Under the latter circumstances, any unused gas remaining in the tank reduces the amount required to refilling and there is no waste of the quantity remaining in the tank after the pressure falls below that required for operation.

The operation of the embodiment shown in FIG. 2O is similar to that described in connection with FIG. 19 and previous figures, except that no power drive or pump for the liquid `supplied to the vaporizer 318 is required. To start, the valve 496 on the propane tank is opened and the pilot light 360 is lit as previously described. The valves 516 and 520 are then opened to supply water from the tank 508 through the valve 52@ and the hose 588 through the vaporizer 318. The pressure regulator 0398 is then adjusted until the gauge 506 reads the desired pressure, for instance p.s.i. The burner valve 354 is then opened and the -burner adjusted to provide the proper steady steam pressure in the vaporizer as shown by the steam gauge 382 as has been previously described. The gauge 506 may show a pressure of for instance 50 p.s.i. which will be, in this embodiment, the pressure applied to the burner and also to the water supply in the tank 508. The operation of this embodiment is otherwise substantially the same as that described in connection with FIG. l9. To terminate operation, the valve 496 may be closed. The valve 516 and the valve 520 may then also be closed to completely shut down the fogger. If operation is resumed again shortly, for instance within an hour or so, and if the water supply as indicated by the water gauge 524 has not been exhausted, operation of the fogger lcan lbe resumed by following the same procedure as described When first starting. However, if operation is not to be resumed until the next day or a longer period, it is desirable to release the gas in the tank 5118 to prevent too much absorption of gas lby the water. This pressure may be released for instance by partially opening the ller cap 512 until the pressure has fallen to atmosphere. This should be done out of doors where released gas is immediately dissipated. The tank 59S may then be completely filled with water and the filler cap replaced. It is then ready for a new start. This procedure prevents the absorption of the gas in the tank 508 by the water which may interfere with the best operation if gas Linder pressure stands for long periods in contact with the water. If the Water in the tank 508 has already absorbed too much gas, the water may be drained from the tank by means of the drain cock 526 and the tank completely refilled with fresh water. No inflammable mixtures can be formed within the tank 508 as long as it is kept full of either propane gas or water. Propane gas mixtures with air in order to be inammable must contain nearly -of air. This condition could never be present with proper operation and, even if it were, a ame or spark would still have to be applied to the interior of the tank. Like a gasoline tank, a propane tank should not stand with its cover removed in the presence of fire. The special features of the operation of the embodiment of FIGS. l, 2, 3, 5, 6 and 7 will now be described. The fogger shown in these gures is similar to the embodiment shown in FIG. 9 except that the fogger in FIG. l is adapted to operate with fuel such as kerosene or furnace oil which requires `a source of heat other than atmospheric temperature for satisfactory vaporization.

It may be mentioned that when LPG consisting mainly of butane or other higher boiling point materials is used, a vaporizer heated by other means besides atmospheric temperature may be required. This may even be true of propane at low atmospheric temperatures when a large amount of fuel is being used from a relatively small fuel tank. It should be noted that the kind of vaporization employed depends on the particular fuel used and the prevailing atmospheric temperature. When the heat of the burner flame is used to vaporize the burner fuel, the surface of the vaporizer and the proximity to the ame may be different for such different conditions. A vaporizer remote from the burner may be employed either heated indirectly fr-om burner heat supply or from an entirely separate heat source other than the atmosphere. Other differences between the embodiment of FIG. 1 and FIG. 9 will be apparent from the descriptions.

Referring particularly to FIG. l and FIG. 7, this fogger is started as follows. The fog material valve 184 should be closed. When the pump 134 has been started and the water valve 142 has been opened, water under pressure will be supplied to the fuel tank 156 through the outlet connections 144, 158, and valve 160 which should be open. The water pressure is indicated by the gauge 148 and may for instance be in the vicinity of 60 p.s.i. This approximate pressure is maintained by the proper adjustment of the pump by-pass valve 152. This pressure 17 is also exerted on the fuel 162 in the tank 156. The priming valve 66 is then opened and fuel flows through the pressure regulator 170 which may be set to maintain a pressure of for instance 40 p.s.i. as indicated by the .gauge 172. Fuel will then flow into the generating pan 62. This fuel is then lit from an external flame and burns heating the vaporizer coil 50. When this is suinciently hot, which may be in a matter of three to five minutes, the burner may be turned on, It may be mentioned that during generation of the burner, the cover 26 may be open. Operation of the pump 134 also supplies water at the pressure indicated by gauge 148 to the vaporizer 45. A quick conector fitting similar to that shown in FIG. 4 is mounted on the end of the vaporizer 45. This is provided with an orifice similar to the orifice 78 but generally somewhat smaller which controls the water supply to the vaporizer. The amount of water passing through this orifice is determined by the size of the orifice and the pressure differs on opposite sides thereof. The water fiows through the vaporizer 45 through the outlet ends 44 and 47 through the steam orifice 86 and out the hollow threaded member 84. The burner valve 68 is now opened slightly and the burner starts. After the vaporizer 50 has been aditionally heated by the burner flame, the burner valve 68 is opened to the proper operating burner setting which may be for instance 31/2. It should be mentioned that the priming valve 66 may be closed except for maintaining the priming re during burner generation. The burner ame during preferred operation may be bluish-yellow and does not extend substantially further toward the outlet than the larger diameter turns of the vaporizer. It is desirable that combustion should be completed toward the inlet end of the combustion duct formed by the inner lining 38. The burner is adjusted to maintain the desired steam pressure in a manner similar to that described in connection with the embodiment of FIGS. 9 and 19 and a similar steam gauge may be provided for this purpose. The proper burner operation can also be determined by adjusting the temperature to keep the issuing steam jet dry and to provide a fairly uniform pressure in the vaporizer. lf pressure uctuations occur, these can be detected by the sound. However, a steam gauge is desirable. The Water pressure as shown by the gauge 148 can be kept reasonably constant by means of a properly constructed and regulated by-pass valve 152. However, better pressure control can be obtained with an additional pressure regulator which may be inserted in the connection 146. A single pressure regulator in the line 144 may also be employed to regulate both the water and fuel pressure. However, this would require the use of the same pressure on the water supply to the vaporizer and the fuel supply to the burner, It has been found that under certain conditions a lower pressure on the fuel to the burner is desirable. When a uniform flow of dry, preferably superheated, steam has been established from the opening in the threaded member 84, the fog oil or formulation valve 184 may be opened. Steam passing through the steam orifice 86 expands, entrains fluid in the space 104 and forms a Vacuum in this space which is communicated to the annular space 102 to the interior of the tube 92 to the interior of the tube 94 through the tube 72 and the quick disconnect ttings 76, the fiexible connection 188, the strainer 186, the valve 184 and the pipe 182 projecting close to the bottom of the fog material tank 178. When the valve is closed, a vacuum is produced within these passages which may be from 1S to 24 inches or thereabouts. A vacuum of 20 inches is satisfactory under certain circumstances of operation which have been carried out. When the valve 184 is opened, fog oil is drawn from the tank 178 by the path previously described to the annular clearance space 104. Here it is picked up by the issuing steam jet finely atomized and discharged as a thermal aerosol out the opening in the threaded member 84. 1n passing through the round opening in the air tube cover 120. air from the inside of the air tube is entrained, thus creating a ow of air into the air tube opening 112 and out the opening 110. The jet issuing from the outlet opening 42 of the nose or outlet cone 16 also augments the flow of combustion gases and air established by the burner in the duct within the inner lining 14. The air tube prevents overheating of the formulation in the nozzle body 82 and the tube 92 and functions in a way similar to that described in connection with the operation of the embodiment of FIG. 9. It will be noted that the nozzle and air tube assembly 32 is located further back from the outlet end of the outlet cone 16 than the corresponding parts shown in FIG. 9. The location of the jet nozzle further from or closer to the outlet of the cone 16 may considerably intiuence the operation. For instance, more heating of the fog oil by the hot combustion gases occurs with the jet nozzle further from the outlet. However, if the temperature of the combustion gases is high and a high rate of inflammable fog oil delivery is employed, there is a possibility of fog oil ignition. This tendency appears to be reduced at least under some circumstances by positioning the jet nozzle closer to the nose outlet as shown in FIG. 9 and FIG. 16.

Referring now to FIG. 8, this shows a diagrammatic View of an embodiment of the invention in which similar numbers indicate the corresponding parts except that a prime has been added to the numbers. The fogger 10 of this embodiment may be the same as shown in FIG. 1 and the fog material tank line and nozzle may be the same as in the previous embodiment. However, the tank 139 may contain for instance No. 2 furnace oil, No- 1 furnace oil, or a mixture of the two. The contents of this tank constitutes fuel for the burner as well as the liquid supplied to the Vaporizer through the connecting member 146. The No. 1 oil is better for burner, but does not form as dense a fog as No. 2 oil. The burner, however, will operate although with a yellower flame on the No. 2 oil. The pump 134 may be operated in the same manner described in the previous embodiment or by other means. The starting, adjusting and operating are similar to that previously described. However, a different burner setting may be required and a different diameter of orifice to determine the amount of oil delivered to the vaporizer 45. If the fog material does not contain, for instance, dissolved insecticide sensitive to heat, the fog material tank and feed line may be completely dispensed with and the fog produced entirely by the jet of vaporized oil or other fog-forming fluid issuing from the steam orifice 82. This arrangement would be especially suitable for producing obscuring fogs for military purposes or fog to prevent freezing for instance in orchards. However, where a heat sensitive insecticide or other material is to be distributed by the fog, its passage through the vaporizer can be avoided by providing a fog material containing a high percentage of insecticide in the tank 178 which passes through the valve 184', the strainer 186', the line 188', the tube 72', the tube 92, the annular passage 102 and the annular clearance 104, and is sucked in and entrained by the oil vapor jet from the orifice 82. In this form of operation, the insecticide is all -contained in the fog material in tank 178'. and is mixed with the pure oil vapor from the tank 139 in the opening in the threaded member 84 and in the jet beyond. With this form of operation, the vaporized oil issuing from the orice 82 dilutes and enhances distribution of the insecticide and may persist longer in the atmosphere and carry greater distances than when water is employed. The use of water or oil in the vaporizer to produce the atomizing jet each have their particular advantages. The use of oil supplied to the vaporizer to produce the atomizing jet may also be employed in the embodiment of FIG. 20 in which case an appropriate oil would be substituted for the water in the tank 508. When an inflammable oil such as No- 2 furnace oil is used in the vaporizer to create the fog jet, there is more likelihood of ignition of the fog at the fog outlet 42 than when water is employed in the vaporizer. This tendency can be reduced by controlling the temperature, the position of the jet nozzle with respect to the fog outlet, and by other means. Also, this dillculty can be completely eliminated by employing the type of fog outlet and jet nozzle shown in the modification of FIG. 8a. The outlet end of the fogger 10 is provided with an upturn combustion gas outlet housing 600. The hot combustion gases pass in a horizontal direction from the duct formed by the inner lining 38 into the housing 600 and are discharged upwardly from the open top 602 of this housing. The end 47 of the vaporizer 44 projects through a hole 604 in the housing 600. The jet nozzle 606 may be similar to that shown at 82, 84, etc. in FIG. 5 or to that indicated by the numbers 426, 430, 436, etc, in FIGS. 16, 17 and 18 except that the air tube 424 is here unnecessary because the combustion gases are deflected upward and do not pass over the nozzle 606. This nozzle is located at a sufllcient distance from the hot gas outlet 602 so that no ignition of the jet from the nozzle 606 can be produced by the hot exhaust gases issuing from outlet 602. The fog oil or formulation is supplied through the tube 72 and 92 to the annular clearance space 104 for instance as shown in FIG. 5. Although the arrangement of FIG. 8a is advantageous for the purpose of preventing fog light up, especially when the fog jet is produced by oil supplied to the vaporizer, it does not provide certain of the advantages which are obtained by mounting the jet nozzle in the outlet cone as shown in other figures, such as FIGS. 5 and 16. One of these advantages is the use of the hot llue gases for additional vaporization of the fog oil. The heat contained in these gases is Wasted in the embodiment shown in FIG. 8a. Another advantage which this embodiment sacrifices is the injector effect of the jet issuing from the jet nozzle in augmenting the llow of hot gases initiated by the burner through the duct around the jet and out the fog outlet. This effect is quite advantageous for stabilizing the operation of the burner. With the jet outlet arrangement shown in FIG. 5 or FIG. 16 the action of the burner is almost entirely independent of external wind conditions due to the augmented flow of the hot gases produced by the jet. With the upturned outlet of FIG. 8a operation in a high wind or at a high vehicle speed may be somewhat erratic. Further, if oil is used instead of water in the vaporizer, the oil is still consumed and fogging cannot be stopped by closing the fog material valve 456. However, if propane is employed as burner fuel as in FIG. 19 or FIG. 20 when oil is supplied to the vaporizer 318 or 45', then fog may be shut oil by closing the burner valve 354 to put out the fire and then closing the valve 142 to stop oil supply to the vaporizer. Fogging is resumed by reopening the burner valve 354 whereupon the pilot light 360 relights the lire. The valve 142' is then also opened. On the other hand, the burner of FIG. 1 and FIG. 8 requires generation to relight except for brief fire stoppage. It will thus be seen that the embodiment shown in FIG. 8a may be more or less advantageous, depending on the particular use and type of operation desix'ed.

Referring again to the operation of the fogger on propane or L.P.G. as illustrated in the embodiments of FIGS. 19 and 20, it should be noted that L.P.G. is a cheap and advantageous fuel which is quite widely available in the United States. In some areas, L.P.G. is substantially cheaper than gasoline or even diesel fuel. It is also advantageous in that it may not require heating of a vaporizer prior to lighting of the burner. The burner may also be turned on and off at will and will relight from the pilot light. The pressure under which propane for instance is stored is also sufficient to deliver the fuel to the burner and also water to the vaporizer, thus eliminating pumps and the power `required to operate them. However, L.P.G. fuels must be stored in pressure-resistant containers. T-hese are more expensive than a kerosene or fuel oil tank. Also, kerosene and fuel oil are more widely obtainable than L.P.G. In fact, in many places in the world where foggers are used L.P.G. is not obtainable at all or would be prohibitively expensive. It will thus be seen that the embodiment of FIG. `1 may be required in some circumstances while the embodiment of FIG. 9 is advantageous in others.

As previously stated, FIG. 21 illustrates an improved modification of the general type of fogger shown in FIG. 9.

The complete fogger unit 610 is 'provided with an outer shell 611. This is supported on two A-frames 612 and 613. Inside the outer shell 611 is an inner shell 614, there being a passage for combustion air 615 between the shells 611 and 614. Inside the shell 614 is an inner liner 616, supported by its flanged ends 617 and 618 on the shell 614. The vaporizer coil 619 is in turn supported on four longitudinal beads 620, pressed inwardly into the inner liner 616, as best shown in FIG. 22. The A-frames 612 and 613 are held together by the shelf 621 at the bottom and by the handle member 622 at the top. The outer shell 611 is held securely at each end in closely fitting bores in the A-frames. A burner cover plate 623 is secured to the A-frame 613 by screws and is spaced away from the A-frame about 1/16" by washers or depressions so as to provide an air space 624 between the cover and the A-frame. This is to provide an anti-resonance air passage. As will be seen in FIG. 22, the A-frames are provided with a series of lands 625, the inner ends of which constitute the bore which locates the inner shell 614. Between the lands 625 are air openings 626 which, when the pressure inside the combustion chamber 627 is reduced by the action of the burner 628 and by the ejector action of the jet nozzle 629, permits the passage of air from the A-frame 612 through the passage 615, through the space between the lands in the A-frame 613 and thence between the end of the shell 614 and the cover 623 into the combustion chamber 627, and thence out the fog outlet 630. This provides an inflow of air from left to right in the opposite direction from the flow of air through the combustion chamber from right to left and preheats the combustion air before its entrance into the combustion chamber; thus reducing heat losses from the combustion chamber and also cooling the exterior. A baille washer 631 having a central hole 632 slightly larger than the burner 628 is attached to the flange 618 and is thus spaced somewhat to the left of the burner 628. A six-point star-type baille 633 is supported on the inner side of the coils of the vaporizer 619. The baille and its elements are desirably made of heat-resistant material, for instance, high nickel and chromium alloy steel or chromium steel alloy. This baille may be composed of three star-shaped discs 634, each disc lhaving six equally-spaced slots 636 and six equallyspaced cutouts between the slots. Each of the six slots in each disc is engaged in one of three slots in each of six spacer strips 635. When the three discs each having six slots are assembled with the six strips, each having three slots engaged in interlocking relation, a paddlewheel structure is formed which, when inserted into the turns of the vaporizer, holds itself together; the strips 635 spacing the discs 634 a fixed distance from the inner surface of the vaporizer 619. A rod 637 engages a hole in one of the strips 635. The other end of the rod 637 passes through a hole in the baflle washer 631 and is secured to it by a thread on the end of the rod and a nut on each side of the baille washer. This spaces the star baille 633 the proper distance from the burner 628 to provide, together with the flow resistance of the baille, desired air flow through the combustion space, pre; 

5. IN A FOGGER HAVING A BOILER, A BURNER HEATING SAID BOILER, A JET NOZZLE CONNECTED TO SAID BOILER, A SOURCE OF FOG-FORMING MATERIAL COMMUNICATING WITH SAID JET NOZZLE AND ADAPTED TO BE ENTRAINED AND DISCHARGED AS A JET THROUGH SAID NOZZLE VIA THE AGENCY OF VAPOR UNDER PRESSURE FROM SAID BOILER, ELECTRICALLY-OPERATED MEANS FOR STARTING AND STOPPING THE FLOW OF FOG-FORMING MATERIAL TO SAID JET NOZZLE, A VALVE MEMBER FOR CUTTING OFF THE FUEL SUPPLY TO SAID BURNER NORMALLY HELD CLOSED, MAIN ELECTRICAL CONTACTS ASSOCIATED WITH SAID FUEL VALVE MEMBER SO AS TO BE CLOSED WHEN SAID FUEL VALVE IS OPENED AND ENERGIZING THE MAIN ELECTRICAL CIRCUITS, A STARTING BUTTON FOR MANUALLY OPENING SAID FUEL VALVE MEMBER, BURNER IGNITION CONTACTS CLOSED WHEN SAID BUTTON IS MANUALLY PRESSED AND OPEN WHEN SAID BUTTON IS RELEASED, LATCH MEANS FOR HOLDING SAID FUEL VALVE IN OPEN POSITION WITH SAID MAIN CONTACTS CLOSED, PRESSURE RESPONSIVE MEANS COMMUNICATING WITH SAID BOILER CONROLLING SAID LATCH MEANS SO THAT SAID FUEL VALVE IS LATCHED OPEN ONLY WHEN THERE IS A CERTAIN PREDETERMINED PRESSURE IN SAID BOILER AND EFFECTING THE UNLATCHING AND CLOSING OF SAID FUEL VALVE MEMBER AND THE OPENING OF SAID MAIN CONTACTS WHEN THE BOILER PRESSURE FALLS BELOW SAID PREDETERMINED VALUE, ELECTRICAL MEANS OPERABLE WHEN SAID MAIN CONTACTS ARE CLOSED TO SUPPLY VAPORIZABLE LIQUID UNDER PRESSURE TO SAID BOILER AND MANUALLY OPERABLE ELECTRIC CONTACT MEANS FOR STOPPING THE FLOW OF FOG MATERIAL TO SAID NOZZLE WHEN OPEN AND FOR STARTING THE FLOW OF FOG MATERIAL ONLY WHEN LAST SAID CONTACTS ARE CLOSED AND SAID MAIN CONTACTS ARE ALSO CLOSED. 